Since the introduction of differing standardized battery sizes (e.g., the American National Standards Institute's C18 series of designations and/or the International Electrotechnical Commission's 60086 standards), device manufacturers have attempted to strike a balance between providing users' of their devices with flexibility to rely on a variety of different battery sizes while simultaneously ensuring that user error in selecting or inserting the batteries into the device would not damage the device or injure the user. Perhaps the most ubiquitous approach was to design battery compartments for the device that would severely restrict the type of battery a user could install, with the most obvious distinction being the introduction of 9 volt (e.g., 6LR61 batteries in IEC nomenclature) in which a prismatic cell container is coupled with uniquely shaped positive and negative terminals on a common top surface of the battery itself.
As users gravitated toward round cylindrical battery sizes, such as AA, AAA, C, and D (e.g., respectively speaking, LR6, LR03, LR14, and LR20 in IEC nomenclature), device manufacturers designed battery compartments with round, cylindrical cavities whose diameter substantially matches the battery size of interest. Leaf or coiled spring contacts situated at the axial ends of the cavity and similarly engineered to only receive and maintain contact with that battery size. Differing examples of this well-known approach are illustrated/described in U.S. Pat. Nos. 6,238,818; 7,309,139; and 8,197,085.
An obvious drawback to this focus on a single size is that it limits the user's options for powering the device. Consequently, a number of schemes have been proposed to enable a device to receive and operate on batteries with differing sizes.
U.S. Pat. No. 8,727,561 shows a portable light or device with a battery compartment having smaller and larger transverse dimensions for receiving batteries of correspondingly smaller and larger sizes. A movable electrical contact adjusts to the appropriate length for the battery.
U.S. Pat. No. 7,909,478 discloses a portable lighting device with a battery compartment that is configured to include two subcompartments that selectively receive batteries of different sizes. One end of the battery compartment includes a contact assembly with first and second contact surfaces having an electrical contact that is common to the first and second surface. A circuit is coupled to the light source in order to provide current from only one of the battery types, and more specifically, to adapt the current based on the type of battery inserted into one of the sub compartments.
U.S. Pat. No. 6,851,828 describes a flashlight having an elongated body with a plurality of differently spaced and sized longitudinal grooves. An end cap is formed with a contact ring that selectively engages coplanar negative poles of the batteries in the elongated body, while a multi-planar contact is interposed at the end of the body which engages the lamp.
United States Patent Publication No. 2005/0122715 shows a flashlight housing with two battery locations capable of accommodating batteries of two different sizes. An electro-mechanical structure ensures that the housing cannot be closed—and, by extension, the light cannot be operated—if two batteries of different sizes are inserted. The use of different sized batteries can result in safety problems if/when the smaller sized battery is fully depleted before the larger sized battery which, in a series-type relationship, gives rise to the larger battery actually charging the smaller battery, thereby generating internal gassing and the potential for leakage.
In view of the foregoing, a device having a battery compartment that can receive different sized batteries, without accidental mixing of batteries of varying sizes, would be welcome. In particular, the compartment should minimize the need for specialized and/or moving parts while simultaneously streamlining the electrical connections and securely retaining the batteries in the event the device is dropped.